android自定義View繪製字符串

1、MainActivity.class類

包

import android.app.Activity;
import android.os.Bundle;
import android.view.Display;
import android.view.View;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;

類的實現

public class MainActivity extends Activity {
	
	public int nScreenWidth = 0;
	public int nScreenHeight = 0;
	Paint paint = null;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {

		//	獲取屏幕寬高
		Display display = getWindowManager().getDefaultDisplay();
		nScreenWidth = display.getWidth();
		nScreenHeight = display.getHeight();
		
		super.onCreate(savedInstanceState);
		setContentView(new FontView(this));
	}
	
	//	自定義的View
	class FontView extends View {
		public final static String STR_WIDTH = "獲取字符寬度爲：";
		public final static String STR_HEIGHT = "獲取字符高度爲：";

		public FontView(Context context) {
			super(context);
			// TODO Auto-generated constructor stub
			paint = new Paint();
		}
		
		@Override
		protected void onDraw(Canvas canvas) {
			super.onDraw(canvas);
			//	設置背景色
			setBackgroundColor(Color.BLACK);
			
			//	設置字符串顏色
			paint.setColor(Color.WHITE);
			canvas.drawText("當前屏幕寬"+nScreenWidth, 0, 30, paint);
			canvas.drawText("當前屏幕高"+nScreenHeight, 0, 60, paint);
			
			//	設置字體大小
			paint.setColor(Color.RED);
			paint.setTextSize(18);
			canvas.drawText("字體大小爲18", 0, 90, paint);
			
			//	消除字體鋸齒
			paint.setFlags(Paint.ANTI_ALIAS_FLAG);
			canvas.drawText("消除字體鋸齒", 0, 120, paint);
			
			//	獲取字符串寬度
			canvas.drawText(STR_WIDTH + getStringWidth(STR_WIDTH), 0, 150, paint);
			
			//	獲取字體高度
			canvas.drawText(STR_HEIGHT + getFontHeight() , 0, 180, paint);
			
		}
		
		//	獲取字體串寬度
		private int getStringWidth(String str) {
			return (int) paint.measureText(str);
		}
		
		//	獲取字體高度
		private int getFontHeight() {
			FontMetrics fm = paint.getFontMetrics();
			return (int) Math.ceil(fm.descent - fm.top) + 2;
		}
	}
}

2、效果圖